There are fears Australian winger Josh Mansour has suffered a serious knee injury after a freak training accident at the Kangaroos St George's Park base in England.

Mansour was carried from the field and taken for scans with doubts surrounding his role in the rest of the tournament.

It was at the end of a small-sided touch football game when Mansour suffered the injury. He immediately cried out in pain and training was stopped, after a collision with teammate Josh Dugan.

Mansour looked to have been shielding the ball after a kick as Dugan attempted to score a try. Training stopped instantly as the players crowded a heartbroken Mansour.

The Penrith winger was to play in Australia's second pool match against New Zealand on Sunday after starring for the Kangaroos in their opening Four-Nations match against Scotland.

Mansour scored two tries and ran for a game high 247 metres as he looked to have cemented his spot on Australia's left wing. Blake Ferguson is expected to earn a Test reprieve now after he was to be overlooked for the game against New Zealand with Mansour and Valentine Holmes having been picked to start on the flanks.